During February, three sternal wound infections occurred among CABG patients. If Dr A performed 28 surgeries, Dr B performed 26, and Dr C performed six, what was the SSI attack rate for CABGs in February?

• A. 3%
• B. 4%
• C. 5%
• D. 6%

Answer: (C)

Calculating an SSI attack rate involves taking the number of sternal wound infections and dividing by the total number of CABG procedures performed during February, then converting to a percentage. There were 3 infections among 28 + 26 + 6 = 60 CABG surgeries, so the rate is 3/60 = 0.05, which is 5%. This uses the total procedures in the period as the denominator, reflecting the proportion of surgeries that developed infection.